1. Field of the Invention
The present invention relates to sleep monitoring and particularly to a method and apparatus for monitoring a person""s sleep through the use of integrated sensors in layer pads.
2. Description of the Related Art
Inadequate sleep is a chronic problem for a significant portion of the population. Consequently, everyday activities, level of function and safety are negatively impacted. The quality of sleep has a direct effect upon waking performance, attitude, and quality of life.
Traditional sleep monitoring or polysomnography is performed in a sleep laboratory, using ten to twenty body-surface sensors (electrodes, elastic bands, etc.) to record the electroencephalogram, electro-oculogram, electromyogram, electrocardiogram, respiratory movement/efforts at thorax and abdomen, oral/nasal airflow, and blood oxygen saturation. The attachment of sensors using glue and tapes and the routing of wires against the skin typically requires ninety minutes or more and is performed by a trained polysomnographic technician. Ambulatory versions of polysomnography uses portable recorders so that the sleep monitoring can occur at the home of the patient. However, a polysomnographic technician is still needed and the same amount of time and effort is necessary to connect all the sensors to the body. All this activity leading up to the patient actually going to sleep dramatically alters a night of xe2x80x9cnatural sleepxe2x80x9d.
Several previous attempts have been made on incorporating sensors into a sleeping mattress so as to do away with the need to connect sensors to the patient""s body for the purpose of gathering data. However, most of these applications only utilize one sensor for collecting one type of data and are therefore not very useful when compared to traditional polysomnography.
A principal objective of the present invention is to provide a home-use sleeping monitoring system that does not require wired sensors to be attached to a subject""s body. The present invention utilizes sensors incorporated in a layer pad that is laid over a conventional mattress, wherein the sensors can collect medically-significant data from the subject. The signals from the sensors are collected by a data acquisition unit and converted to data that can be analyzed or stored for later analysis. This system does not require any specialized training to use as there are no sensors to attach to the body. This system requires no extra effort on the subject""s part to prepare for the sleep data collection prior to sleeping. Because of all these advantages, this system can be used in the subject""s home for an extended period of time to collect continuous sleep data.
The present invention can also be used for monitoring infants diagnosed with a high risk of Sudden Infant Death Syndrome (SIDS) and for field emergency applications.
In view of the forgoing objectives, a method of the present invention utilizes sensors incorporated in a layer pad which is laid on top of a conventional mattress on which the subject sleeps. The sensors can collect information such as the subject""s position, temperature, sound, vibration, movement, and optionally other physical properties.
The apparatus for monitoring an individual""s sleep quality comprises one or more layers of arrays of integrated sensors, which can be incorporated in layer pads, which is then placed on a conventional mattress; one or more controllers coupled with the arrays of integrated sensors in each layer pad for the purpose of acquiring data from the sensors; a real-time analysis software for analyzing data acquired by the controller from the array of integrated sensors; an interface software for collecting user lifestyle data; a lifestyle correlation software for correlating the lifestyle data with the data acquired by said array of sensors; one or more active components to improve sleep quality based on the data acquired through the sensors and the lifestyle data. The array of sensors provide one or more of the following data: position, temperature, sound, vibration, and movement data. Each layer pad can be individually removed or added as necessary depending on the data being collected.
The controller can be an embedded controller, a desktop personal computer or a laptop computer.
The real-time analysis software transforms the data collected by the controller from time domain to event and/or frequency domain. The real-time analysis software can also extract body temperature, position and movement, mattress pressure, breathing and heart rate, snoring, and bruxism information.
The real-time analysis software can compute means, variances, characteristic frequencies, and counts from the data and calculate an index of nightly restlessness.
The user lifestyle data collected can be such things as the last time and how much a meal was eaten, how much medication, vitamins, and products containing caffeine and alcohol were consumed, estimate of stress level, amount and intensity of exercise, and an estimation of the quality of sleep just experienced overnight.
The lifestyle correlation software provides correlation analysis between any of the data collected by the controller and by the lifestyle software. The lifestyle correlation software utilizes aggregate data from several days to several months to compute and present long-term averages, trends, and singularities.
The active components that alter the quality of sleep can be one or more of the following: a temperature control system to alter the mattress or room temperature based on the body temperature data, a wake-up alarm that is activated based on a particular point in a person""s circadian rhythm, a lighting control system to change the ambient light level using window blinds or computer-controlled room lights, and an active tilting mattress support activated to encourage a person to roll over to alleviate snoring.